Hello,
I picked up my 02 STS used with about 60k miles, it always seemed to have a tire shake. The dealer was a friend and his guys went over and over this car replacing and rebalancing etc but still it shook.
Finally we all agreed it must be the tires (lots of complaints on the internet concerning the Goodyears on it seemed to back that theory...)
So we drove it that way for about 25k miles.

Lately theGoodyears just wouldn't keep air for more than a couple days without popping warnings... and they made a kind of "squishing" sound at low speed... and the ride was deteriorating...These Goodyear's were not all that worn but they looked/sounded awful and there was that shaking at speed.

As a resultI put a new set of Michelin's on it to the tune of about $1k.
The ride changed dramatically... Itrides/handles like new...
EXCEPT:
On the way home it started to shake at about 63mph so afterjust oneday I took it back and had all four tires rebalanced... and rotated...Although the shake seemed to "change" in quality it is still there.

So here I am: 2 different sets of pretty expensive tires, at least 4-5 balances done between them and lots of eyballs all over the car yet I still have this shake...

It really takes away from the enjoyment of driving this beautiful car...

I do also have an RSScode C0620 Right Front Position Sensor malfunction, but that only started recently after I had some work done under the hood...
Any ideas?
Thanks.
Jim

 

Jim, I've too had this issue since purchasing my 05 Deville. I've since replaced the tires with Goddyear Assurance. Notably the right rear seems to be where the shake (past about 68mph) comes from, so the wheel was removed and found to be out of round. The tire was replaced and still the shake continued, only this time it seemed to now consume not only the passenger seat but the front dash and steering wheel as well. I even went so far as to buy a new "true" wheel and place it on that right rear side which offered a dampening but still a shake. I'm really at my witts end here. One mech suggested that one or both front drive shafts could have run out or have a bad "CV" joint. Has ANYONE a bit of advice or suggestions or had the same problem as us? Could it possibly be the same thing? It's depressing to own a cadillac and have it ride like a Geo. Thanks, Kevin

 

Most Cadillac dealers will have a book that is a gathering of all bulletins from a couple of years. Bulletins, unlike recalls, are "in the field" reported repairs for things like this. I have one for my 91 Allante separate from the factory service manual. It covers all Cadillac bulletins from 90 to 91. Get friendly with the service advisor to be able to read the book.

 

i too have the same with my '99 sts.... almost a mirror to your story...... and too have spent big $$ to try to correct...... at this point i have learned to live with it. i will say that there are times that it is not there (the shimmy) and times it is. mine starts at 66 mph, and seems to go away at 77 mph..... you know i might add that it seems more like a vibration, in that if it were front end problem i shouldfeel it in the steering wheel, and if problem were rear i should feel it in the seat......

my arms are still up in the air on this one....??????? so hopin maybe someone might have some answers.........

wheel bearing??? i really havent had these checked. maybe that will be next.....

please, lets keep the forum posted on this one.........

rickyd

also need to mention.... the vibration is more pronounced when i give er a little gas in that cruising speed, 66 to 77 mph. and seems to go away when i am off gas.........

 

HOLY Sh** rickyd, i have the EXACT! same problem with my 99 STS. I have done the same as everyone on here....Mulitple tires....numerous Balances!! rotations etc!!!! and nothing. You are 100% right Rick, its everything you described i thought same thing "you know i might add that it seems more like a vibration, in that if it were front end problem i shouldfeel it in the steering wheel, and if problem were rear i should feel it in the seat......" i cant figure that either and how when you accerlate it gets worse than "seems" to go away when you let off. I have had car 3 years now and been searching for an answer ever since! Will be keeping my eye on this post.

 

have you had any break workdone? frt,rr.........

ya know too..... ??? do you think the viberation is there at lower speed, though we just dont feel it? its not as pronounced.

how many miles on your sts?

 

yea i had break work done both front and rear (did my self) didnt see anything out of ordinary in there actually when i did it everything looked somewhat "new" in front end. I had car three years exaclty bought with 105K now i have 145K on it and since first day i bought it i drive it back from NJ to FL on I-95 and whole trip i was experimenting with the shimmy shake. and till this day its the same.

It might be there at lower speeds but i dont think because having drove long periods of time at speeds from 40- all the way to 60 its a smooth as can be. but i think your right it feels more like a "vibration" because steering wheel doesnt shake and i dont feel it in the seat.

 

but its weird because i read somehwere once that the "sts chassis is sensitive to harmonic frequencies" because when i re balance the wheelslike every couplemonths it gets better but still there. Maybe it just the type of rims cadillac used. I also heard that having the wheels "road forced" will show any irregularaties if any..

*excuse spelling please*

 

gotcha.... yea, lets hope someone on the Forum might have some answers.....

hey guy, and oil leaks? and how much oil do you use between oil changes.... its something us n* owners are use to i guess.... lol

Jimkana dont mean to take your thread over....sorry.....maybe we'll get some answers for everyone. jump in

rickyd

 

yea i have an oil leak that started at about 108K im guessing but it might be rear main seal. If tkae drivers wheel off you can see from side oil/grease around where oil pan bolts up. I use about quart every 800 miles w/ leak and N* usage combined..but yea used to it..